I think it’s pretty safe to say that I’m not a big fan of the supplement industry. That doesn’t mean that I think that all supplements are useless, just the vast majority of them (like weight gainers, for example).
Recently, I came across an excellent book called Waterlogged: The Serious Problem of Overhydration in Endurance Sports by Timothy Noakes. This book did a fantastic job of dismantling the voodoo science of sports drink industry. For years now we have been told by sports scientists that we need to be constantly ingesting fluids while we exercise lest we want our performance to suffer or collapse because of heatstroke or lack of electrolytes.
But guess what?
It’s all nonsense. None of it is supported by science (at least the science conducted by independent researchers).
In Waterlogged, Tim Noakes goes into exhaustive detail on the science of hydration (essentially discussing every study in detail on the topic) in order to separate fact from fiction. Suffice it to say that his findings were quite eye opening, which is why I wanted to share some of the key highlights with you in this article.
So let’s dive in!
Dehydration is no big deal
Back in the day dehydration was never an issue for endurance athletes. In fact, runners and cyclists were actively discouraged from ingesting too much water for fear that it would negatively impact their performance.
For example, here is some common advice that was given to marathon runners back in 1907:
“Don’t take any nourishment before going seventeen or eighteen miles. If you do, you will never go the distance.”
“Don’t get in the habit of drinking and eating in a marathon race; some prominent runners do, but it is not beneficial.”
This proscription against drinking water was so pervasive back then that runners were actually shamed from drinking excessively, as Jackie Mekler (a former ultramarathon champion runner) states in the book:
“It was common amongst runners that drinking was seen as a sign of tiredness – thus if any other was seen to be drinking frequently or excessively his opponents would interpret it as a sign of weakness.”
Conversely, it was the ability to run an entire marathon without a drop of liquid that was seen as the ultimate ideal and the true test of a runner’s ability, as Mekler remarks:
“To run a complete marathon without any fluid replacement was regarded as the ultimate aim of most runners; and a test of their fitness.”
Talk about a far cry from the advice of sports scientists today who recommend that we should always be “drinking ahead of our thirst” in order to avoid even minor levels of dehydration. Surely the runners of today’s era (backed by cutting edge sports science) are much better athletes than their forefathers.
Runners actually did just fine back in the day when they were discouraged from drinking water and there were no issues of them passing out or collapsing from dehydration. As Noakes mentions in the book, the runners from today’s era are actually no better than them:
“The introduction and encouragement of frequent drinking after 1976 were not associated with any sudden increase in world-record performances in the marathon.”
In fact, since the introduction of the “drink ahead of thirst” philosophy the collective performance of runners has actually suffered. This makes sense when research has consistently shown that the runners who lose the most amount of body weight (i.e. are the most dehydrated) tend to also be the fastest or among the top finishers. As Tim explains in the book:
“The best athletes in the world are typically those who lose the most weight during exercise, who have the least thirst, and who run the fastest when they are quite markedly dehydrated, perhaps because the weight loss is beneficial to performance.”
“Time and again, studies, even those by researchers expecting different outcomes, have shown that the runners who are the most dehydrated, as measured by percentage of body weight loss, run the fastest.”
What about electrolytes?
Some of you might be thinking, “Okay, maybe you don’t need much water during a marathon or triathlon, but you definitely need electrolytes (i.e. salt and potassium) in order to avoid muscle cramps and a subsequent decrease in performance.”
Blood sodium levels in the human body are tightly regulated. When your diet contains plenty of salt (like the typical Western diet) the body excretes the excess through your sweat in order to maintain its balance. Conversely, the opposite occurs when your diet contains less salt, your body simply holds on to more of it. It’s an exquisitely fine-tuned system.
And studies have routinely shown that endurance athletes simply do not lose enough salt through their sweat in order to significantly affect their blood sodium levels. At least not enough to warrant gulping down sports drinks and salt tablets. As Noakes points out, you simply don’t need additional salt, even as an endurance athlete:
“Despite an average daily salt intake in the United States of ~10 to ~15 g, which greatly exceeds the minimum expected daily requirement of perhaps 3 g in habitual exercises, the myth has developed that all U.S. athletes are at risk of becoming salt deficient especially when they run marathons or complete in ultradistance events like the Ironman Hawaii Triathlon or the Western States 100-mile race.”
If anything, the pancreas will actually add electrolytes to any fluid you ingest regardless if it contains electrolytes or not. This is done in order to optimize the absorption of fluids by the body. So in the end there really is no need to worry about ingesting additional electrolytes.
What about muscle cramps?
Contrary to popular belief, there simply is no science linking electrolyte depletion to muscle cramps. As far as we know muscle cramps are simply the result of neuromuscular fatigue (i.e. overworking the muscle beyond its capacity).
Noakes sums up his thoughts sports drinks and salt deficiency quite nicely:
“The sports drink industry has staked its claims on the principles of salt deficiency, proclaiming that the sodium consumed in a person’s general diet is not enough and that sodium supplementation, via-electrolyte containing sports drinks, can prevent muscle cramps, heat illness, and sodium deficiency during long-duration exercise. These claims ignore the body’s exquisite regulations of sodium concentration and a wealth of research on the subject.”
What about heatstroke?
Another common misconception touched on in the book is the idea that dehydration can cause heatstroke in athletes. This is yet another reason why we are instructed to “drink ahead of thirst.” According to Noakes there is absolutely no science to back up this claim:
“No study has ever shown that athletes with heatstroke are more dehydrated than those control subjects who complete the same activities but without developing heatstroke.”
That’s because it’s not the duration or length of the exercise that increases the risk of heatstroke, but rather its intensity. In other words, you’re far more likely to develop heatstroke from running a 5k or 10K than you are from running a marathon or an ultramarathon:
“The incidence of heatstroke is most common in exercise of short duration, for example, races of less than 21 km, which are usually completed within an hour (by those at risk of developing heatstroke) and in which high levels of “dangerous dehydration” simply cannot occur.”
And if you think the environment plays a significant role in heatstroke think again. According to the science a fair number of heatstroke cases actually during the cooler, early morning hours:
“Many cases of heatstroke occur in environmental conditions that are too cool to seriously challenge the extraordinary human heat-losing capacity. For example, a study of exertional heat illness in the U.S. Marine Corps reported that ‘Most of the cases occurred during the cooler early morning hours when recruits performed strenuous exercise.’”
Ultimately, the cause of heatstroke has more to do with abnormal heat production by the body than anything else:
“Heatstroke is caused not by abnormalities in the heat-dissipating mechanisms but by a state of abnormal heat production – what we have called excessive endogenous heat production – which produces heat so rapidly that the heat-dissipating mechanisms of the body are overwhelmed.”
So much for the idea of “drinking ahead of thirst” and guzzling down sports drinks to in order to prevent heatstroke. The science is pretty clear that there is no evidence supporting this line of reasoning.
Are sports drinks good for anything?
I’m sure at this point you’re wondering, “Are there any benefits at all to ingesting sports drinks as an athlete?”
The carbohydrates found in sports drinks are actually beneficial and science has shown that the ingestion of carbohydrates during endurance exercise can improve performance.
And it’s not because the carbohydrates necessarily provide energy to your body, but rather the effect the ingestion of them has on your brain:
“It is now known that besides the prevention of hypoglycemia, glucose ingestion aids performance during running by lowering the perception of effort at any running speed, thereby allowing a faster running speed at the same level of psychic effort. That this effect is due to a central brain effect is also now properly recognized.”
This is why studies have shown that just swishing a carbohydrate laced beverage in your mouth and spitting it out can increase your performance to a similar degree if you had ingested the beverage normally.
But the beauty of this understanding is that you don’t need to go out and buy overpriced sports drinks in order to cash in on the performance benefits. The same benefits can be obtained by simply mixing some simple sugars (like dextrose) in water.
In a nutshell, hydration research on athletes has determined the following:
- Dehydration is not a big deal and doesn’t hinder a runner’s performance. In fact, marathon runners back in the day excelled during an era when they were actively discouraged from drinking water.
- The body does not lose dangerous amounts of electrolytes during long runs (at least not enough to hinder performance) and muscle cramps are not caused by low sodium levels.
- Heatstroke is not caused by dehydration but rather by abnormal levels of heat production in the body.
The fact is that the human body has evolved a finely-tuned thirst mechanism and a superior capacity to lose heat by sweating making us excellent long-distance runners in extreme dry heat environments. This is why African bushmen can run for several hours in the Kalahari Desert in high temperatures with little water, or as Noakes explains:
“The biological record appears to give a consistent answer: Humans developed as long-distance runners especially well adapted to run in extreme dry heat in the middle of the day while drinking infrequently and conserving body sodium stores.”
The science in Waterlogged is pretty clear, we simply don’t need sports drinks.
And for those of you who are really interested in this stuff, I can’t recommend Waterlogged enough, even if you’re not an endurance athlete like myself.
Here’s to staying fit!